Camera lens module

ABSTRACT

A lens module includes a lens barrel, a lens holder, a base, a plurality of elastic guiding members secured on the base and a plurality of electromagnetic devices arranged on the base. The lens barrel has a plurality of optical components received therein, and outer screw threads formed on an outer wall thereof. The lens holder has inner screw threads formed on an inner wall thereof to engage with the outer screw threads of the lens barrel. A plurality of supporting bars and magnetic elements are secured on an outer wall of the lens barrel. The guiding members each is formed on the base and configured for inserting of the respective supporting bar therein to guide a movement of the lens holder. The electromagnetic devices each locates at opposite sides of the respective magnetic element of the lens holder to provide a force to drive the lens holder.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of patent application,entitled “CAMERA LENS MODULE”, with application Ser. No. 12/110,536filed on Apr. 28, 2008, now U.S. Pat. No. 7,764,448. The content of theabove-referenced application is hereby incorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to camera lens, and particularly to acamera lens module used in portable electronic devices, such as mobilephones.

2. Description of the Related Art

With the ongoing development of microcircuitry and multimediatechnologies, digital cameras are now in widespread use. Portableelectronic devices, such as mobile phones and personal digitalassistants (PDAs), are being developed to be increasinglymulti-functional. Many of these portable electronic devices are nowequipped with a digital camera module.

In a typical camera module, a lens module is a key element in producinghigh quality pictures. Generally, a camera module includes a lens moduleand an image sensing module. Optical image signals are focused by thelens module onto the image sensing module. The image sensing moduletransforms the optical image signals into electronic image signals. Whena distance between the lens module and the image sensing module isadjusted, the definition of the optical image signals received by theimage sensing module is also changed. Focusing mechanisms are widelyused in camera modules (both digital and film-based) for creating highquality photos.

Conventionally, the lens module includes a lens barrel, a lens holderfor receiving the lens barrel therein, and a motor for performing thefocusing process. The motor drives the lens barrel to rotate threadedlyin the lens holder for focusing. However, most motors have complexconfigurations, which increase the cost of the camera module. Inaddition, friction between the lens holder and the lens barrel retardsmovement of the lens barrel resulting in low efficiency of the cameramodule.

What is needed, therefore, is an improved camera lens module.

SUMMARY OF THE INVENTION

A lens module includes a lens barrel, a number of lenses, a lens holder,a base, a number of elastic guiding members, and a number ofelectromagnetic devices. The lenses are received in the lens barrel. Thelens barrel is threadedly engaged in the lens holder, and the lensholder has an outer surface, a number of supporting bars extending fromthe outer surface, and a number of magnetic elements secured on theouter surface. The elastic guiding members are formed on the base andaround the lens holder. A distal free end of each of the supporting barsis inserted in the respective elastic guiding member. Theelectromagnetic devices are around the lens holder. Each electromagneticdevice is arranged at opposite sides of the respective magnetic element.Each electromagnetic device is configured for interacting with therespective magnetic element to move the lens holder. Each elasticguiding member is configured for preventing the lens holder fromrotating. The elastic guiding members each include a frame, a retainingportion at a center of the frame, and two elastic portions symmetricallylocated at two flanks of the retaining portion and connecting theretaining portion and two sides of the frame respectively. The elasticportions are a combination of a spring and a metal strip.

Other advantages and novel features of the present invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present apparatus can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present apparatus. Moreover,in the drawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is an isometric view of a camera module in accordance with afirst embodiment of the present disclosure;

FIG. 2 is a schematic, cross-sectional view of the camera module in FIG.1, taken along line II-II;

FIG. 3 is an isometric view of a camera module in accordance with asecond embodiment of the present disclosure;

FIG. 4 is an isometric view of a camera module in accordance with athird embodiment of the present disclosure; and

FIG. 5 is an isometric view of a camera module in accordance with afourth embodiment of the present disclosure.

DETAILED DESCRIPTION

Referring to FIGS. 1-2, a camera module 100 in accordance with a firstembodiment of the present disclosure comprises an image sensing module20 and a lens module 10 arranged on the image sensing module 20.

The lens module 10 comprises a base 13, a cylindrical lens holder 16 anda cylindrical lens barrel 14 engaged with the lens holder 16. The lensbarrel 14 has two lenses 11 and 12 received therein. A pair of guidingmembers 15 and a pair of electromagnetic devices 17 are arranged on thebase 13 and around the lens holder 16.

The lenses 11, 12 can be made of glass or plastic material. Outer screwthreads (not labeled) are formed on an outer wall of the lens barrel 14.Inner screw threads (not labeled) are formed on an inner wall of thelens holder 16. The lens barrel 14 and the lens holder 16 arethreadingly engaged with each other. A position of the lens barrel 14relative to the lens holder 16 can be adjusted according to differentrequirements. Two supporting bars 162 extend outwardly from an outerwall of the lens holder 16. The two supporting bars 162 are symmetricalto an axis of the lens holder 16. Two magnetic elements 164, such aspermanent magnets, are mounted on the outer wall of the lens holder 16.For convenient description, a top end of each magnetic element 164 isdefined as north (N) pole, and a bottom end of each magnetic element 164is defined as south (S) pole. The two magnetic elements 164 are alsosymmetrical to the axis of the lens holder 16. The magnetic elements 164and the supporting bars 162 are in a same horizontal level and evenlylocated around the lens holder 16 in an interval fashion.

The base 13 is made of plastic material. The base 13 has a recessedspace 131 defined at a bottom end thereof and a center hole (notlabeled) defined at a top end thereof communicating with the space 131.The lens holder 16 can pass through the hole and move along a mechanicalaxis thereof for focusing.

Each of the guiding members 15 is bent and has a right-angledconfiguration. Each of the guiding members 15 comprises a frame (notlabeled), a retaining portion 154 at a center of the frame and twoconnecting strips 152 located symmetrically at two flanks of theretaining portion 154. The two connecting strips 152 connect theretaining portion 154 with two sides, i.e. right and left sides of theframe respectively. The connecting strips 152 are made of elasticmaterial allowing the retaining portion 154 to move up and down at acertain range. A hole (not labeled) is defined in the retaining portion154. The guiding members 15 can be made of a piece of metal plate with athickness in a range of 0.2˜1.0 millimeter by a punching process andthen bent to form a right-angled configuration. In the presentembodiment, the guiding members 15 are made of an alloy of aluminum andmagnesium with a thickness of 0.3 millimeters. The two guiding members15 are arranged around the lens holder 16 symmetrically. The twosupporting bars 162 of the lens holder 16 insert into the holes of theretaining portions 154 of the two guiding members 15 respectively, andare secured by adhesive.

Each of the electromagnetic devices 17 has a first electromagneticwinding 172 at an upper end thereof and a second electromagnetic winding174 at a bottom end thereof. Each of the first and secondelectromagnetic windings 172, 174 comprises a ferromagnetic plate (notlabeled) and a winding (not labeled) wrapped around the ferromagneticplate. Wrapping orientations of the two electromagnetic windings 172,174 are opposite. The two electromagnetic devices 17 are arrangedadjacent to the lens holder 16 corresponding to the position of themagnetic elements 164 to surround the magnetic elements 164 and securedon the base 13 by insert molding. The first electromagnetic winding 172is adjacent to the N pole of the magnetic elements 164. The secondelectromagnetic winding 174 is adjacent to the S pole of the magneticelements 164.

The image sensing module 20 comprises a circuit board 24 attached to thebase 13 and an image sensor 22 mounted on the circuit board 24. Thecircuit board 24 electrically connects to the first and secondelectromagnetic windings 172, 174 and supply power, control signals,etc. to the first and second electromagnetic windings 172, 174. Theimage sensor 22 is received in the space 131 of the base 13. The imagesensor 22 and the lenses 11, 12 are aligned perpendicularly forreceiving optical signals passing therethrough.

When the first and second electromagnetic windings 172, 174 have noelectricity, the location of the lens holder 16 is at a balance positionwhere the connecting strips 152 have no elastic distortion. Whenelectricity is supplied to the first and second electromagnetic windings172, 174, magnetic poles of ends of the first and second electromagneticwindings 172, 174 which are adjacent to the magnetic elements 164 (i.e.,a bottom end of the first electromagnetic winding 172 and an upper endof the second electromagnetic winding 174) are the same because of theopposite wrapping orientations thereof. Specifically, for example, whenthe first and second electromagnetic windings 172, 174 are supplied withelectricity along a first direction, the bottom end of the firstelectromagnetic winding 172 generates an N pole, and the upper end ofthe second electromagnetic winding 174 generates an N pole. The firstelectromagnetic windings 172 push the magnetic elements 164, and thesecond electromagnetic windings 174 pull the magnetic elements 164.Thus, the lens holder 16 with the lenses 11, 12 can move down along amechanical axis thereof for focusing. Due to the elasticity of theconnecting strips 152 of the guiding members 15, the retaining portions154 can move downward with the supporting bars 162 of the lens holder16. The two connecting strips 152 evenly pull the supporting bars 162 ofthe lens holder 16 along two opposite directions (i.e., along clockwiseand anticlockwise directions) at the horizontal level to prevent thelens holder 16 rotating along the axis of the lens holder 16.

When the first and second electromagnetic windings 172, 174 are suppliedwith electricity along a second direction opposite to the firstdirection, the lens holder 16 moves up along the mechanical axis thereofto perform another focusing process. Compared with the lens holder heldand guided by screw threads in conventional camera module, the guidingmember 15 of the present disclosure can guide the movement of the lensholder 16 with no lag.

Referring to FIG. 3, a camera module 200 in accordance with a secondembodiment of the present disclosure is shown. The camera module 200 issimilar to the camera module 100 of the first embodiment of the presentdisclosure. The differences therebetween are that springs 152 a of eachof the guiding members 15 a replace the connecting strips 152 of each ofthe guiding members 15; and the springs 152 a are parallel to the axisof the lens holder 16, i.e., the springs 152 a connect a retainingportion 154 a and top and bottom sides of the frame of each of theguiding members 15 a respectively.

Referring to FIG. 4, a camera module 200 in accordance with a thirdembodiment of the present disclosure is shown. The camera module 300 issimilar to the camera module 100 of the first embodiment of the presentdisclosure. The differences are that the connecting strips 152 of eachof the guiding members 15 are replaced by an isosceles triangle-shapedconnecting portion 153 b and a traversed T-shaped connecting portion 152b. The triangle-shaped connecting portions 153 b and a top of theT-shaped connecting portions 152 b of each of the guiding member 15 bare hollowed. A bottom side of the triangle-shaped connecting portion153 b connects to the retaining portion 154 b. A top of thetriangle-shaped connecting portion 153 b connects to a top of theT-shaped connecting portion 152 b. Compared with the connecting strips152 of the guiding member 15 of the first embodiment of the presentdisclosure, the triangle-shaped connecting portions 153 b and theT-shaped connecting portions 152 b have higher intensity.

Referring to FIG. 5, a camera module 400 in accordance with a fourthembodiment of the present disclosure is shown. The camera module 400 issimilar to the camera module 300 of the third embodiment of the presentdisclosure. The differences are that the traversed T-shaped connectingportions 152 b of each of the guiding member 15 b are replaced by aspring 152 c. In other words, the springs 152 c of each of a guidingmember 15 c connect a top of triangle-shaped connecting portions 153 cand a side of frame of the guiding member 15 c.

It is believed that the present disclosure and its advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made thereto without departing from the spiritand scope of the disclosure or sacrificing all of its materialadvantages, the examples hereinbefore described merely being preferredor exemplary embodiments of the disclosure.

1. A lens module, comprising: a lens barrel; a plurality of lensesreceived in the lens barrel; a lens holder, the lens barrel threadedlyengaged in the lens holder, and the lens holder having an outer surface,a plurality of supporting bars extending from the outer surface and aplurality of magnetic elements secured on the outer surface; a base; aplurality of elastic guiding members formed on the base and around thelens holder, a distal free end of each of the supporting bars beinginserted in the respective elastic guiding member; and a plurality ofelectromagnetic devices being around the lens holder with eachelectromagnetic device arranged at opposite sides of the respectivemagnetic element, each electromagnetic device configured for interactingwith the respective magnetic element to move the lens holder, eachelastic guiding member configured for preventing the lens holder fromrotating, wherein the elastic guiding members each comprise a frame, aretaining portion at a center of the frame and two elastic portionssymmetrically located at two flanks of the retaining portion andconnecting the retaining portion and two sides of the framerespectively, and the elastic portions are a combination of a spring anda metal strip.
 2. The lens module as claimed in claim 1, wherein theplurality of supporting bars includes two supporting bars symmetricallyextending from opposite sides of the lens holder, and the plurality ofmagnetic elements includes two magnetic elements symmetrically securedon another two opposite sides of the lens holder, the supporting barsand the magnetic elements arranged in an alternate fashion.
 3. The lensmodule as claimed in claim 2, wherein the two supporting bars and thetwo magnetic elements are coplanar.
 4. The lens module as claimed inclaim 1, wherein the retaining portion defines a hole therein with thedistal free end of the corresponding supporting bar inserted therein. 5.The lens module as claimed in claim 1, wherein the elastic guidingmember has a right angle configuration.
 6. The lens module as claimed inclaim 1, wherein the electromagnetic devices each comprise a firstelectromagnetic winding at a top thereof and a second electromagneticwinding at a bottom thereof, and the two electromagnetic windingsgenerate opposite magnetic poles to act with the magnetic element.
 7. Acamera module, comprising: a lens barrel having outer screw threads onan outer surface thereof; a plurality of optical components received inthe lens barrel; a lens holder receiving the lens barrel therein, thelens holder having inner screw threads formed on an inner wall thereofto engage with the outer screw threads of the lens barrel, and having aplurality of supporting bars and a plurality of magnetic elementssecured on an outer wall; a base with a recessed space defined at abottom thereof and a hole defined at a top thereof, the hole incommunication with the space; a plurality of elastic guiding membersformed on the base and around the lens holder, a distal end of each ofthe supporting bars being inserted in the respective guiding member; aplurality of electromagnetic devices being around the lens holder witheach electromagnetic device arranged at opposite sides of the respectivemagnetic element, each electromagnetic device configured for interactingwith the respective magnetic element to move the lens holder and eachelastic guiding member configured for preventing the lens holder fromrotating; and an image sensor received in the space of the base, whereinthe elastic guiding members each comprise a frame, a retaining portionat a center of the frame and two elastic portions symmetrically locatedat two flanks of the retaining portion and connecting the retainingportion and two sides of the frame respectively, and the elasticportions are a combination of a spring and a metal strip.
 8. The cameramodule as claimed in claim 7, wherein the retaining portion defines ahole therein with the distal end of the corresponding supporting barinserted therein.
 9. The camera module as claimed in claim 7, whereinthe plurality of supporting bars includes two supporting barssymmetrically extending from opposite sides of the lens holder, and theplurality of magnetic elements includes two magnetic elementssymmetrically secured on another two opposite sides of the lens holder,the supporting bars and the magnetic elements arranged in an alternatefashion.
 10. The camera module as claimed in claim 9, wherein theplurality of guiding members includes two guiding members and theplurality of electromagnetic devices includes two electromagneticdevices, and the two guiding members are accommodated corresponding tothe two supporting bars and the two electromagnetic devices areaccommodated corresponding to the two magnetic elements.
 11. The cameramodule as claimed in claim 10, further comprising a circuit board,wherein the image sensor is mounted on the circuit board, and thecircuit board is attached to the base and electrically connected to thetwo electromagnetic devices.